State police say they've been unable to determine what caused a Washington County farmhouse fire that killed a young mother and her 5-year-old son.

Lisa Marie Hewitt, 27, was pronounced dead early Monday morning. Investigators say she was holding her son, Timothy Adam Hewitt Jr., inside their family's home on Wigington Road in Buffalo Township, when they were both killed.(Photos: Fatal house fire in Buffalo Township)

"When I arrived, we didn't know where the child was," Coroner Tim Warco said. "But I found the child huddled beneath mom, as we do in these cases."

Troopers from the Washington barracks say the fire started around 11 p.m. Sunday in the living room of the home, but they're unsure how. Although it remains under investigation, police don't suspect criminal activity or that the fire was suspicious.

Investigators said they believe Hewitt tried to call 911 soon after the fire broke out, but the line went silent. Family members said Hewitt then called her husband, Timothy Hewitt Sr., who was at work.

"Tim talked to her and told her to break out a window, and she said it was getting hard to breathe and the little boy was screaming in the background," said Peg Teegarden, Timothy Hewitt's aunt.

Teegarden said when her nephew arrived at his home, the flames were so intense that not even the firefighters could enter.

"The whole bottom floor was completely ablaze. Smoke was coming out of the roof real bad and it wasn't long that the whole second floor was ablaze before the first truck got here," said Pat O'Brien, assistant chief for Taylorstown.

Hewitt's uncle, Edwin Medlen, arrived around the same time.

"I'm really lost for words. This isn't the first time I tried to get over to help him," said Medlen.

Family said Timothy Hewitt had suffered tragedy before.

"This was the third child that he lost, and now this time he lost his wife, too," said Teegarden. She said her nephew was so distraught this time, he was taken to the hospital.

"They were great people, couldn't ask for any better," said Medlen. "(I used to) play with the baby. He was like my own. They were all like my own."

"It's traumatic. I've been doing this a long time and fires are a devastating way to perish," Warco said.

Photos: Fatal house fire in Buffalo Township

Photos: Fatal house fire in Buffalo Township

A Washington County mother died while trying to protect her son as a fire broke out inside their home.

Lisa Marie Hewitt, 27, was pronounced dead early Monday morning. Investigators found her near her 5-year-old son, Timothy Adam Hewitt Jr., on the second floor of the family's home on Wigington Road in Buffalo Township.

"When I arrived, we didn't know where the child was," said Tim Warco, Washington County coroner. "But I found the child huddled beneath mom, as we do in these cases."

The fire started around 11 p.m. Sunday. Hewitt's uncle, Edwin Medlen, arrived to find their home engulfed in flames.

"I'm really lost for words. This isn't the first time I tried to get over to help him," said Medlen.

Extra crews were on hand to assist the fire department. Investigators say they believe Hewitt tried to call 911 for help soon after the fire broke out, but the line went silent.

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